This invention relates to hand stamps and more particularly to a hand stamp that allows the user to stack multiple stamps one on top of the other. This invention also allows the interchangeability of either a rubber die and inkpad stamp or a self inking stamp to be used in the stacking design.
In the first embodiment, the stamp uses a printing surface made from an ink permeable material that allows ink to pass from an ink reservoir, cartridge or other ink storage media, through the printing surface and onto the object being marked. This eliminates the need for a separate stamp inkpad. These stamps are referred to as hand stamps.
This type of stamp is illustrated in U.S. Pat. No. 5,942,312 issued to Venkataraman et al. This patent discloses a pre-inked thermoplastic foam which has open cells in the area that is designed to transfer ink and closed or sealed cells in the area which is designed to be impermeable to ink. The pre-inked thermoplastic foam is pre-inked before the image is formed on the thermoplastic material. Thus if there is a problem with the image, the entire pad including the ink, is wasted. Furthermore there may be difficulties in forming an image on a pre-inked thermoplastic foam as it may be messy or require special handling due to the ink in the pre-inked thermoplastic foam. The pre-inked thermoplastic foam is mechanically held to the stamp and assembled at the factory. The pre-inked thermoplastic foam is not designed to be installed or removed in the field, nor is it stackable.
U.S. Pat. No. 5,996,493 issued to Okumura et al. illustrates a pre-inked stamp that uses an ink pack to supply ink to the porous stamp. The ink pack ruptures when the ink pack is pressed against a cutting device in the stamp. There is a transparent film thermally attached to the stamp surface to protect the stamp surface during transport and storage. The transparent film is removed just before using the stamp for printing images. The porous stamp portion is thermally attached to the holder at the factory and is not designed to be installed in the field nor is it stackable.
Another stamp is disclosed in U.S. Pat. No. 6,164,202 issued to Takami. This patent discloses a stamp unit comprising a holder, which is placed in a stamp manufacturing device for making a stamping surface on a stamp material. The holder interacts with the stamp manufacturing device to properly position the holder in the manufacturing device. An image is formed on the surface of the stamp forming material by fusing portions on the surface. The stamp forming material is saturated with ink and ink is allowed to flow out from the non fused portions onto a printing sheet forming the image.
In the second embodiment, the stamp's printing surface is made from rubber or other flexible material. The printing surface is securely mounted on a handle that is grasped by the user. There are raised numbers, letters and other indicia on the face of the printing surface of the stamp. The printing surface is placed in contact with an inkpad so that ink is transferred to the raised indicia. The inked printing surface is pressed against the receiving surface and ink is transferred from the raised indicia onto the ink receiving surface. Repetition of the stamping process requires that the printing surface be pressed against the inkpad each time an image is to be transferred.
A problem not solved by the prior art devices is providing a stackable stamp that permits either embodiment of hand stamp, i.e. the stamp pad and printing surface with raised indicia or the self inking stamp to be stacked by utilizing similar frame components. Providing stackability allows several stamps with different indicia to be stacked one on top of the other. This minimizes desk and storage space while providing the user all of the benefits of individually made stamps that are not stackable. It is also desirable if the stamp is designed for both embodiments to be intermixed and stacked on top of each other.
Applicant's invention addresses and solves the problems of the prior art devices. The invention comprises a frame member that supports both embodiments of the image forming layer. In the first embodiment, the frame supports an ink cartridge that has an ink storage layer and a porous foam layer with an image forming stamp material on the surface. The two layers are in intimate contact with each other and are supported by the frame member. The image forming layer is made of a porous resin layer. Portions of the porous resin layer are melted and solidify into impermeable areas that are ink impermeable, and other portions of the porous resin layer remain unmelted and allow ink to pass. In this manner the stamping image is defined. The frame member can alternatively support the second embodiment of a rubber die with raised indicia thereon. The raised indicia defines the image, which when inked, can transfer the image to an image receiving surface.
There is a bottom tray that covers the rubber die or the foam layer with the image thereon. The bottom tray acts as a dust cover if there is a foam layer. An inkpad is inserted into the tray if there is a rubber die with raised indicia thereon. The bottom tray has a center post that is received into a receiving hole on the top surface of a stamp positioned below the upper stamp. In this manner the frame members and their associated image forming surface can be stacked one on top of the other.